Downhole vacuum sub

ABSTRACT

A vacuum sub ( 8 ) for use in a well bore ( 12 ), the vacuum sub ( 8 ) having a cylindrical casing ( 28 ) with an upstream end ( 14 ) and a downstream end ( 16 ). The upstream and downstream ends ( 14, 16 ) are designed to attach to components of a downhole assembly ( 6 ) in a well bore ( 12 ). The vacuum sub ( 8 ) includes a port ( 18 ) in the cylindrical casing ( 28 ) that provides access between the inside ( 20 ) of the cylindrical casing ( 28 ) to the outside ( 22 ) of the cylindrical casing ( 28 ). The port ( 18 ) is angled so that when air passes through the port ( 18 ) from the inside ( 20 ) of the casing ( 28 ) to the outside ( 22 ) of the casing ( 28 ), the air is directed upwardly through the well bore ( 12 ) in an upstream direction, thereby creating a vacuum in the well bore ( 12 ) below the port ( 18 ).

CLAIM TO PRIORITY

This application claims priority from U.S. Provisional Patent Application No. 61/644,215 filed on May 8, 2012.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to downhole tools for use in the assisting of cleaning out, drilling out or drilling new oil, gas or water wells. In particular, the invention relates to a downhole sub designed to assist in the circulating of the hole with air, air mist or foam in the completion, work-over or drilling of a well in any environment.

2. Description of the Prior Art

Circulation is the process of pumping drilling mud down a well bore to the drill bit, and then back up to the surface, during work-over, completion, or drilling of an oil, gas or water well. During this process the reservoir pressures at the bottom of a well may be less than the weight of the column of mud in the well bore, which can lead to the loss of circulation or flow of the mud into the formation, rather than returning to the surface. This loss of circulation can lead to a wide range of problems, including but not limited to an inability to carry debris from the bottom of the well to the surface. Accordingly, it is important that the circulation be maintained within the well bore.

Accordingly, there is a need for use of air or foam that improves or establishes circulation in well bores having low pore point pressure.

3. Identification of the Objects of the Invention

An object of this invention is to provide a tool and method that assists in the circulation of an oil, gas or water well by creating a vacuum in the well bore.

Another object of the invention is to provide a tool and method that assists in circulation of an oil, gas or water well by creating a pressure differential within a well bore that circulates fluid in the well bore, thereby carrying debris toward the surface of the well bore.

SUMMARY OF THE INVENTION

The invention is embodied in one or more vacuum subs for use in a well bore. The vacuum sub includes a cylindrical casing with upstream and a downstream ends designed to attach to components of a downhole assembly of a drill string in a well bore. The casing includes a port that is upwardly angled to allow air, air mist or foam to pass from the inside of the drill string to the outside of the drill string in an upward direction toward the surface of the well bore thereby creating a vacuum in the well bore below the ports.

The method according to the invention provides a vacuum sub with a port arranged to allow air, air mist or foam to pass from the inside of the vacuum sub to the outside of the vacuum sub directing the air upstream toward the surface of the well bore, and creates a vacuum in the well bore below the port and thereby improving circulation in an oil, gas or water well.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated in the accompanying drawings wherein,

FIG. 1 is a schematic view of an oil, gas or water well assembly, including a vacuum sub or subs according to an embodiment of the present invention; and

FIG. 2 is a cross-sectional view of the vacuum sub of the invention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The aspects, features, and advantages of the invention mentioned above are described in more detail by reference to the drawings, wherein like reference numerals represent like elements.

FIG. 1 illustrates a typical oil, gas or water well assembly including a drilling rig/pulling unit 2 positioned on the earth's surface 4 with a drill string 10 received by a downhole assembly 6 including a vacuum sub 8 extending down into a well bore 12.

Although the particular well assembly shown in FIG. 1 is land-based, the vacuum sub of the invention may be used in other types of oil, gas or water well assemblies including off-shore oil or gas well assemblies.

FIG. 2 shows an enlarged view of the vacuum sub 8 of the present invention. The vacuum sub is made from a cylindrical casing 28 containing a threaded upstream end 14 and a threaded downstream end 16 designed for engagement with other downhole components in the well bore. The vacuum sub includes a port 18 that provides access from the inside of the vacuum sub 20 through the inside port opening 24, located below or further downstream than the outside opening 26, to the outside of the vacuum sub 22.

In practice, the vacuum sub is positioned in the well bore as shown in FIG. 1. Air, air mist or foam is pumped down the inside of the drill string forcing air, air mist or foam out the port on the vacuum sub at a desired rate of approximately 600 standard cubic feet per minute (scfm). This rate can be increased or decreased as needed depending on well conditions. Due to the angle of the port, the exiting air, air mist or foam tends to flow out of the port in an upstream direction toward the surface of the well bore. As the air flows in this way, it creates a pressure differential, or vacuum, within the well bore. The portion of the well bore below the port has a lower pressure that the portion above the port. This vacuum creates a vortex in the well bore below the port, thereby establishing or increasing circulation in the well bore. While one embodiment of the invention has been illustrated in detail, the invention is not limited to those skilled in the art. Such modifications and adaptations are in the spirit and scope of the invention as set forth herein. 

What is claimed:
 1. A vacuum sub for use in a well bore comprising, a cylindrical casing (28) having an upstream end (14) and a downstream end (16) arranged and designed to attach to components of a downhole assembly (6) in a well bore (12); said casing including a port (18) that provides access between the inside (20) and the outside (22) of the cylindrical casing (28); said port (18) is angled through said casing so that when air passes through the port (18) from the inside (20) of the casing (28) to the outside (22) of the casing (28), the air is directed up the well bore (12) in an upstream direction toward the surface of the well bore (12), thereby creating a vacuum in the well bore (12) below the port (18).
 2. A method of circulating air in an oil, gas or water well, comprising the steps of: providing a cylindrical casing (8) within a well bore (12), the casing (8) having a port (18) arranged to allow air to pass from inside (20) of the casing (8) to the outside (22) of the casing (8), so that air is directed in an upstream direction toward the surface of the well bore (12); applying air to the vacuum sub (8) so that the air passes through the port (18) and into the well bore (12) in an upstream direction, thereby creating a vacuum in the well bore (12) below the port (18).
 3. The method of claim 2, wherein, the air passes through the port at the rate of approximately 600 scfm. 